Research Of Self-Interference Cancellation Scheme In Massive MIMO Full-Duplex System

Massive MIMO full-duplex system can improve the spectral and energy efficiency significantly by sharing the same time-frequency resource and deploying the large-scale antenna arrays for obtaining the extra spatial multiplexing gain,become a promising candidate for 5G.However,the interferences are unavoidable in massive MIMO full-duplex system,and they would reduce the system performance significantly.Especially,the self-interference due to signal leakage from output to its input at base station,mainly lead to the sum rate loss.Therefore,How to eliminate self-interference effectively is essential.The research of this paper is supported by the national major projects for science:“Research on polarimetric self-interference cancellation in full-duplex system based on additive Gaussianized phase noise(61501050)”and“Research on power amplifier energy efficience based on cognitive and polarization signal processing(61271177)”.Focuses on the problems of self-interference cancellation(SIC)in massive MIMO full-duplex system,the coupling channel estimation based SIC scheme and the energy efficiency optimization based SIC scheme are proposed,respectively.The proposed SIC scheme can eliminate self-interference effectively to improve the spectral and energy efficiency significantly.The main work of this paper is following three aspects:(1)This paper analyzes and summarizes the current research status of self-interference cancellation in massive MIMO full-duplex system,which include the operating mode,advantage and main challenge in massive MIMO full-duplex system.Furthermore,the current works about the SIC scheme are briefly summarized.In addition,it pointed that the lack of the instantaneous information of the self-interference channel and the energy efficiency loss are the main challenge for self-interference cancellation.(2)This paper proposes the coupling channel estimation based SIC scheme to eliminate SI effecti-vely without the instantaneous information of self-interference channel.The proposed SIC scheme firstly estimate the coupling coefficients between the SI channel matrix and the transmit beamforming matrix,then rebuilt the SI copy and subtract it directly for eliminating SI.Furthermore,the simulation results presents that the proposed SIC scheme can eliminate SI effectively,and when the number of antennas and transmit power is very high,the proposed SIC scheme can achieve the same performance with the ideal SIC scheme.(3)This paper proposes the energy efficiency optimization based SIC scheme to eliminate SI effectively and improve the energy efficiency simultaneously.This scheme firstly derive and analyze the sum achievable rate and energy efficiency in closed form to determine the optimizing parameters,which both affect the spectral and energy efficiency.These optimizing parameters include the number of antennas,the transmit power and the pilot power during the channel estimation phase.Then the energy efficiency optimization based SIC scheme is provided to improve the energy efficiency when maintaining a satisfied performance of SI cancellation.The simulation results shows that the proposed SIC scheme can eliminate SI effectively,and compared with the SIC scheme without considering the energy efficiency,the proposed SIC scheme can improve the energy efficiency significantly,but a slightly loss in sum achievable rate.This paper proposed two SIC scheme to eliminate the SI effectively for improving both the spectral and energy efficiency,which provide a new way to eliminate SI in massive MIMO full-duplex system.